/*
 * InputAttribute.java July 2006
 *
 * Copyright (C) 2006, Niall Gallagher <niallg@users.sf.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

package wx.xml.simpleframework.xml.stream;

import wx.xml.stax.api.stream.Location;

/**
 * The <code>InputAttribute</code> is used to represent an attribute
 * within an element. Rather than representing an attribute as a
 * name value pair of strings, an attribute is instead represented
 * as an input node, in the same manner as an element. The reason
 * for representing an attribute in this way is such that a uniform
 * means of extracting and parsing values can be used for inputs.
 *
 * @author Niall Gallagher
 */
class InputAttribute implements InputNode {

    /**
     * This is the parent node to this attribute instance.
     */
    private InputNode parent;

    /**
     * This is the reference associated with this attribute node.
     */
    private String reference;

    /**
     * This is the prefix associated with this attribute node.
     */
    private String prefix;

    /**
     * Represents the name of this input attribute instance.
     */
    private String name;

    /**
     * Represents the value for this input attribute instance.
     */
    private String value;

    /**
     * This is the source associated with this input attribute.
     */
    private Object source;

    /**
     * Constructor for the <code>InputAttribute</code> object. This
     * is used to create an input attribute using the provided name
     * and value, all other values for this input node will be null.
     *
     * @param parent this is the parent node to this attribute
     * @param name   this is the name for this attribute object
     * @param value  this is the value for this attribute object
     */
    public InputAttribute(InputNode parent, String name, String value) {
        this.parent = parent;
        this.value = value;
        this.name = name;
    }

    /**
     * Constructor for the <code>InputAttribute</code> object. This
     * is used to create an input attribute using the provided name
     * and value, all other values for this input node will be null.
     *
     * @param parent    this is the parent node to this attribute
     * @param attribute this is the attribute containing the details
     */
    public InputAttribute(InputNode parent, Attribute attribute) {
        this.reference = attribute.getReference();
        this.prefix = attribute.getPrefix();
        this.source = attribute.getSource();
        this.value = attribute.getValue();
        this.name = attribute.getName();
        this.parent = parent;
    }

    /**
     * This is used to return the source object for this node. This
     * is used primarily as a means to determine which XML provider
     * is parsing the source document and producing the nodes. It
     * is useful to be able to determine the XML provider like this.
     *
     * @return this returns the source of this input node
     */
    @Override
    public Object getSource() {
        return source;
    }

    /**
     * This is used to acquire the <code>Node</code> that is the
     * parent of this node. This will return the node that is
     * the direct parent of this node and allows for siblings to
     * make use of nodes with their parents if required.
     *
     * @return this returns the parent node for this node
     */
    @Override
    public InputNode getParent() {
        return parent;
    }

    /**
     * This provides the position of this node within the document.
     * This allows the user of this node to report problems with
     * the location within the document, allowing the XML to be
     * debugged if it does not match the class schema.
     *
     * @return this returns the position of the XML read cursor
     */
    @Override
    public Location getLocation() {
        return parent.getLocation();
    }

    /**
     * Returns the name of the node that this represents. This is
     * an immutable property and will not change for this node.
     *
     * @return returns the name of the node that this represents
     */
    @Override
    public String getName() {
        return name;
    }

    /**
     * This is used to acquire the namespace prefix for the node.
     * If there is no namespace prefix for the node then this will
     * return null. Acquiring the prefix enables the qualification
     * of the node to be determined. It also allows nodes to be
     * grouped by its prefix and allows group operations.
     *
     * @return this returns the prefix associated with this node
     */
    public String getPrefix() {
        return prefix;
    }

    /**
     * This allows the namespace reference URI to be determined.
     * A reference is a globally unique string that allows the
     * node to be identified. Typically the reference will be a URI
     * but it can be any unique string used to identify the node.
     * This allows the node to be identified within the namespace.
     *
     * @return this returns the associated namespace reference URI
     */
    @Override
    public String getReference() {
        return reference;
    }

    /**
     * Returns the value for the node that this represents. This
     * is an immutable value for the node and cannot be changed.
     *
     * @return the name of the value for this node instance
     */
    public String getValue() {
        return value;
    }

    /**
     * This method is used to determine if this node is the root
     * node for the XML document. This will return false as this
     * node can never be the root node because it is an attribute.
     *
     * @return this will always return false for attribute nodes
     */
    @Override
    public boolean isRoot() {
        return false;
    }

    /**
     * This is used to determine if this node is an element. This
     * node instance can not be an element so this method returns
     * false. Returning null tells the users of this node that any
     * attributes added to the node map will be permenantly lost.
     *
     * @return this returns false as this is an attribute node
     */
    @Override
    public boolean isElement() {
        return false;
    }

    /**
     * Because the <code>InputAttribute</code> object represents an
     * attribute this method will return null. If nodes are added
     * to the node map the values will not be available here.
     *
     * @return this always returns null for a requested attribute
     */
    public InputNode getAttribute(String name) {
        return null;
    }

    /**
     * Because the <code>InputAttribute</code> object represents an
     * attribute this method will return an empty map. If nodes are
     * added to the node map the values will not be maintained.
     *
     * @return this always returns an empty node map of attributes
     */
    @Override
    public NodeMap<InputNode> getAttributes() {
        return new InputNodeMap(this);
    }

    /**
     * Because the <code>InputAttribute</code> object represents an
     * attribute this method will return null. An attribute is a
     * simple name value pair an so can not contain any child nodes.
     *
     * @return this always returns null for a requested child node
     */
    @Override
    public InputNode getNext() {
        return null;
    }

    /**
     * Because the <code>InputAttribute</code> object represents an
     * attribute this method will return null. An attribute is a
     * simple name value pair an so can not contain any child nodes.
     *
     * @param name this is the name of the next expected element
     * @return this always returns null for a requested child node
     */
    @Override
    public InputNode getNext(String name) {
        return null;
    }

    /**
     * This method is used to skip all child elements from this
     * element. This allows elements to be effectively skipped such
     * that when parsing a document if an element is not required
     * then that element can be completely removed from the XML.
     */
    @Override
    public void skip() {
        return;
    }

    /**
     * This is used to determine if this input node is empty. An
     * empty node is one with no attributes or children. This can
     * be used to determine if a given node represents an empty
     * entity, with which no extra data can be extracted.
     *
     * @return this will always return false as it has a value
     */
    @Override
    public boolean isEmpty() {
        return false;
    }

    @Override
    public String debugDescription() {
        return String.format("%s %s %s", parent.getName(), getName(), getValue());
    }

    /**
     * This is the string representation of the attribute. It is
     * used for debugging purposes. When evaluating the attribute
     * the to string can be used to print out the attribute name.
     *
     * @return this returns a text description of the attribute
     */
    public String toString() {
        return String.format("attribute %s='%s'", name, value);
    }


}
